Chemical preparations for use in the permanent or cold waving and straightening of hair are known. Among these are alkaline compositions containing a bisulphite or sulfite compound. Such compositions are disclosed in U.S. Pat. No. 2,836,185, U.S. Pat. No. 3,864,476 and British Pat. No. 849,045. Bisulphite/sulfite hair treating preparations are to be distinguished from waving and/or straightening preparations based on the use of other compounds such as ammonium thio compounds, thioglycolic acid and thiols.
When waving or straightening hair with alkaline bisulphite or sulfite preparations particularly, sulphur and hydrogen bonds as well as various salt linkages within the hair are broken upon contacting with the waving and straightening preparation. To reestablish the broken bonds in the newly waved or straightened position and thus "lock in" and set the hair, oxidizing preparations such as those containing hydrogen peroxide are often used.
Special mention is made of the compositions disclosed in U.S. Pat. No. 3,864,476, incorporated herein by reference. This describes alkaline solutions for the waving and straightening of hair, comprising acidic metal bisulphite, alkali metal borate, alkali metal carbonate, alkanolamine and water. These are disclosed for use in combination with a neutralizing solution which contains hydrogen peroxide.
The foregoing preparations do not always provide the desired degree of curl tightness and springiness and the hair does not retain its curl for as long a period as desirable. Also, the use of hydrogen peroxide in conjunction with the alkaline bisulphite preparation sometimes results in hair lightening, which is undesirable.